The occult scaffolding on this card is late and traceable. The Hermetic Order of the Golden Dawn assigned the first trump the Hebrew letter Beth, the planet Mercury, and the twelfth path of the Tree of Life, running from Kether to Binah. That triple assignment, letter, planet or sign, path, is a Golden Dawn system of the late 1880s and 1890s, built on Eliphas Levi's earlier and different arrangement of the 1850s, which in turn built on the Comte de Mellet's bare alphabet correspondence of 1781. It is not medieval, it is not Egyptian, and no fifteenth-century card-maker had any of it in mind.
Crowley pushed the identification furthest, renaming the card the Magus and treating it as the principle by which the unmanifest becomes an utterance, the word that makes, and therefore also the lie that deceives, since for Crowley every act of speech falsifies what it names. That double edge restores something of the mountebank. Waite is more restrained and reads the figure as the channel of divine will into the world.
In practice the card is read across a fairly wide band: focused will, resourcefulness, the moment when capability meets opportunity, the beginning of a work. The shadow readings are manipulation, self-promotion without substance, and the misuse of a genuine skill. Whether those shadow senses require the card to be reversed is exactly the dispute that divides Waite-derived practice from Marseille practice. Waite lists reversed meanings; many readers get the same range from the card upright by reading it against what surrounds it.